1 files changed, 228 insertions, 285 deletions

diff --git a/net/core/dst.c b/net/core/dst.c
index ca4231ec7347..e9d35f49c9e7 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * net/core/dst.c	Protocol independent destination cache.
  *
@@ -20,171 +21,43 @@
 #include <net/net_namespace.h>
 #include <linux/sched.h>
 #include <linux/prefetch.h>
+#include <net/lwtunnel.h>
+#include <net/xfrm.h>
 
 #include <net/dst.h>
+#include <net/dst_metadata.h>
 
-/*
- * Theory of operations:
- * 1) We use a list, protected by a spinlock, to add
- *    new entries from both BH and non-BH context.
- * 2) In order to keep spinlock held for a small delay,
- *    we use a second list where are stored long lived
- *    entries, that are handled by the garbage collect thread
- *    fired by a workqueue.
- * 3) This list is guarded by a mutex,
- *    so that the gc_task and dst_dev_event() can be synchronized.
- */
-
-/*
- * We want to keep lock & list close together
- * to dirty as few cache lines as possible in __dst_free().
- * As this is not a very strong hint, we dont force an alignment on SMP.
- */
-static struct {
-	spinlock_t		lock;
-	struct dst_entry	*list;
-	unsigned long		timer_inc;
-	unsigned long		timer_expires;
-} dst_garbage = {
-	.lock = __SPIN_LOCK_UNLOCKED(dst_garbage.lock),
-	.timer_inc = DST_GC_MAX,
-};
-static void dst_gc_task(struct work_struct *work);
-static void ___dst_free(struct dst_entry *dst);
-
-static DECLARE_DELAYED_WORK(dst_gc_work, dst_gc_task);
-
-static DEFINE_MUTEX(dst_gc_mutex);
-/*
- * long lived entries are maintained in this list, guarded by dst_gc_mutex
- */
-static struct dst_entry         *dst_busy_list;
-
-static void dst_gc_task(struct work_struct *work)
-{
-	int    delayed = 0;
-	int    work_performed = 0;
-	unsigned long expires = ~0L;
-	struct dst_entry *dst, *next, head;
-	struct dst_entry *last = &head;
-
-	mutex_lock(&dst_gc_mutex);
-	next = dst_busy_list;
-
-loop:
-	while ((dst = next) != NULL) {
-		next = dst->next;
-		prefetch(&next->next);
-		cond_resched();
-		if (likely(atomic_read(&dst->__refcnt))) {
-			last->next = dst;
-			last = dst;
-			delayed++;
-			continue;
-		}
-		work_performed++;
-
-		dst = dst_destroy(dst);
-		if (dst) {
-			/* NOHASH and still referenced. Unless it is already
-			 * on gc list, invalidate it and add to gc list.
-			 *
-			 * Note: this is temporary. Actually, NOHASH dst's
-			 * must be obsoleted when parent is obsoleted.
-			 * But we do not have state "obsoleted, but
-			 * referenced by parent", so it is right.
-			 */
-			if (dst->obsolete > 0)
-				continue;
-
-			___dst_free(dst);
-			dst->next = next;
-			next = dst;
-		}
-	}
-
-	spin_lock_bh(&dst_garbage.lock);
-	next = dst_garbage.list;
-	if (next) {
-		dst_garbage.list = NULL;
-		spin_unlock_bh(&dst_garbage.lock);
-		goto loop;
-	}
-	last->next = NULL;
-	dst_busy_list = head.next;
-	if (!dst_busy_list)
-		dst_garbage.timer_inc = DST_GC_MAX;
-	else {
-		/*
-		 * if we freed less than 1/10 of delayed entries,
-		 * we can sleep longer.
-		 */
-		if (work_performed <= delayed/10) {
-			dst_garbage.timer_expires += dst_garbage.timer_inc;
-			if (dst_garbage.timer_expires > DST_GC_MAX)
-				dst_garbage.timer_expires = DST_GC_MAX;
-			dst_garbage.timer_inc += DST_GC_INC;
-		} else {
-			dst_garbage.timer_inc = DST_GC_INC;
-			dst_garbage.timer_expires = DST_GC_MIN;
-		}
-		expires = dst_garbage.timer_expires;
-		/*
-		 * if the next desired timer is more than 4 seconds in the
-		 * future then round the timer to whole seconds
-		 */
-		if (expires > 4*HZ)
-			expires = round_jiffies_relative(expires);
-		schedule_delayed_work(&dst_gc_work, expires);
-	}
-
-	spin_unlock_bh(&dst_garbage.lock);
-	mutex_unlock(&dst_gc_mutex);
-}
-
-int dst_discard(struct sk_buff *skb)
+int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb)
 {
 	kfree_skb(skb);
 	return 0;
 }
-EXPORT_SYMBOL(dst_discard);
+EXPORT_SYMBOL(dst_discard_out);
 
-const u32 dst_default_metrics[RTAX_MAX + 1] = {
+const struct dst_metrics dst_default_metrics = {
 	/* This initializer is needed to force linker to place this variable
 	 * into const section. Otherwise it might end into bss section.
 	 * We really want to avoid false sharing on this variable, and catch
 	 * any writes on it.
 	 */
-	[RTAX_MAX] = 0xdeadbeef,
+	.refcnt = REFCOUNT_INIT(1),
 };
+EXPORT_SYMBOL(dst_default_metrics);
 
-
-void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
-		int initial_ref, int initial_obsolete, unsigned short flags)
+void dst_init(struct dst_entry *dst, struct dst_ops *ops,
+	      struct net_device *dev, int initial_obsolete,
+	      unsigned short flags)
 {
-	struct dst_entry *dst;
-
-	if (ops->gc && dst_entries_get_fast(ops) > ops->gc_thresh) {
-		if (ops->gc(ops))
-			return NULL;
-	}
-	dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);
-	if (!dst)
-		return NULL;
-	dst->child = NULL;
 	dst->dev = dev;
-	if (dev)
-		dev_hold(dev);
+	netdev_hold(dev, &dst->dev_tracker, GFP_ATOMIC);
 	dst->ops = ops;
-	dst_init_metrics(dst, dst_default_metrics, true);
+	dst_init_metrics(dst, dst_default_metrics.metrics, true);
 	dst->expires = 0UL;
-	dst->path = dst;
-	dst->from = NULL;
 #ifdef CONFIG_XFRM
 	dst->xfrm = NULL;
 #endif
 	dst->input = dst_discard;
-	dst->output = dst_discard;
+	dst->output = dst_discard_out;
 	dst->error = 0;
 	dst->obsolete = initial_obsolete;
 	dst->header_len = 0;
@@ -192,118 +65,155 @@ void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
 #ifdef CONFIG_IP_ROUTE_CLASSID
 	dst->tclassid = 0;
 #endif
-	atomic_set(&dst->__refcnt, initial_ref);
+	dst->lwtstate = NULL;
+	rcuref_init(&dst->__rcuref, 1);
+	INIT_LIST_HEAD(&dst->rt_uncached);
 	dst->__use = 0;
 	dst->lastuse = jiffies;
 	dst->flags = flags;
-	dst->pending_confirm = 0;
-	dst->next = NULL;
 	if (!(flags & DST_NOCOUNT))
 		dst_entries_add(ops, 1);
-	return dst;
 }
-EXPORT_SYMBOL(dst_alloc);
+EXPORT_SYMBOL(dst_init);
 
-static void ___dst_free(struct dst_entry *dst)
+void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
+		int initial_obsolete, unsigned short flags)
 {
-	/* The first case (dev==NULL) is required, when
-	   protocol module is unloaded.
-	 */
-	if (dst->dev == NULL || !(dst->dev->flags&IFF_UP))
-		dst->input = dst->output = dst_discard;
-	dst->obsolete = DST_OBSOLETE_DEAD;
+	struct dst_entry *dst;
+
+	if (ops->gc &&
+	    !(flags & DST_NOCOUNT) &&
+	    dst_entries_get_fast(ops) > ops->gc_thresh)
+		ops->gc(ops);
+
+	dst = kmem_cache_alloc(ops->kmem_cachep, GFP_ATOMIC);
+	if (!dst)
+		return NULL;
+
+	dst_init(dst, ops, dev, initial_obsolete, flags);
+
+	return dst;
 }
+EXPORT_SYMBOL(dst_alloc);
 
-void __dst_free(struct dst_entry *dst)
+static void dst_destroy(struct dst_entry *dst)
 {
-	spin_lock_bh(&dst_garbage.lock);
-	___dst_free(dst);
-	dst->next = dst_garbage.list;
-	dst_garbage.list = dst;
-	if (dst_garbage.timer_inc > DST_GC_INC) {
-		dst_garbage.timer_inc = DST_GC_INC;
-		dst_garbage.timer_expires = DST_GC_MIN;
-		mod_delayed_work(system_wq, &dst_gc_work,
-				 dst_garbage.timer_expires);
+	struct dst_entry *child = NULL;
+
+	smp_rmb();
+
+#ifdef CONFIG_XFRM
+	if (dst->xfrm) {
+		struct xfrm_dst *xdst = (struct xfrm_dst *) dst;
+
+		child = xdst->child;
 	}
-	spin_unlock_bh(&dst_garbage.lock);
+#endif
+	if (dst->ops->destroy)
+		dst->ops->destroy(dst);
+	netdev_put(dst->dev, &dst->dev_tracker);
+
+	lwtstate_put(dst->lwtstate);
+
+	if (dst->flags & DST_METADATA)
+		metadata_dst_free((struct metadata_dst *)dst);
+	else
+		kmem_cache_free(dst->ops->kmem_cachep, dst);
+
+	dst = child;
+	if (dst)
+		dst_release_immediate(dst);
 }
-EXPORT_SYMBOL(__dst_free);
 
-struct dst_entry *dst_destroy(struct dst_entry * dst)
+static void dst_destroy_rcu(struct rcu_head *head)
 {
-	struct dst_entry *child;
+	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
 
-	smp_rmb();
+	dst_destroy(dst);
+}
 
-again:
-	child = dst->child;
+/* Operations to mark dst as DEAD and clean up the net device referenced
+ * by dst:
+ * 1. put the dst under blackhole interface and discard all tx/rx packets
+ *    on this route.
+ * 2. release the net_device
+ * This function should be called when removing routes from the fib tree
+ * in preparation for a NETDEV_DOWN/NETDEV_UNREGISTER event and also to
+ * make the next dst_ops->check() fail.
+ */
+void dst_dev_put(struct dst_entry *dst)
+{
+	struct net_device *dev = dst->dev;
+
+	WRITE_ONCE(dst->obsolete, DST_OBSOLETE_DEAD);
+	if (dst->ops->ifdown)
+		dst->ops->ifdown(dst, dev);
+	WRITE_ONCE(dst->input, dst_discard);
+	WRITE_ONCE(dst->output, dst_discard_out);
+	rcu_assign_pointer(dst->dev_rcu, blackhole_netdev);
+	netdev_ref_replace(dev, blackhole_netdev, &dst->dev_tracker,
+			   GFP_ATOMIC);
+}
+EXPORT_SYMBOL(dst_dev_put);
 
+static void dst_count_dec(struct dst_entry *dst)
+{
 	if (!(dst->flags & DST_NOCOUNT))
 		dst_entries_add(dst->ops, -1);
+}
 
-	if (dst->ops->destroy)
-		dst->ops->destroy(dst);
-	if (dst->dev)
-		dev_put(dst->dev);
-	kmem_cache_free(dst->ops->kmem_cachep, dst);
+void dst_release(struct dst_entry *dst)
+{
+	if (dst && rcuref_put(&dst->__rcuref)) {
+#ifdef CONFIG_DST_CACHE
+		if (dst->flags & DST_METADATA) {
+			struct metadata_dst *md_dst = (struct metadata_dst *)dst;
 
-	dst = child;
-	if (dst) {
-		int nohash = dst->flags & DST_NOHASH;
-
-		if (atomic_dec_and_test(&dst->__refcnt)) {
-			/* We were real parent of this dst, so kill child. */
-			if (nohash)
-				goto again;
-		} else {
-			/* Child is still referenced, return it for freeing. */
-			if (nohash)
-				return dst;
-			/* Child is still in his hash table */
+			if (md_dst->type == METADATA_IP_TUNNEL)
+				dst_cache_reset_now(&md_dst->u.tun_info.dst_cache);
 		}
+#endif
+		dst_count_dec(dst);
+		call_rcu_hurry(&dst->rcu_head, dst_destroy_rcu);
 	}
-	return NULL;
 }
-EXPORT_SYMBOL(dst_destroy);
+EXPORT_SYMBOL(dst_release);
 
-void dst_release(struct dst_entry *dst)
+void dst_release_immediate(struct dst_entry *dst)
 {
-	if (dst) {
-		int newrefcnt;
-
-		newrefcnt = atomic_dec_return(&dst->__refcnt);
-		WARN_ON(newrefcnt < 0);
-		if (unlikely(dst->flags & DST_NOCACHE) && !newrefcnt) {
-			dst = dst_destroy(dst);
-			if (dst)
-				__dst_free(dst);
-		}
+	if (dst && rcuref_put(&dst->__rcuref)) {
+		dst_count_dec(dst);
+		dst_destroy(dst);
 	}
 }
-EXPORT_SYMBOL(dst_release);
+EXPORT_SYMBOL(dst_release_immediate);
 
 u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old)
 {
-	u32 *p = kmalloc(sizeof(u32) * RTAX_MAX, GFP_ATOMIC);
+	struct dst_metrics *p = kmalloc(sizeof(*p), GFP_ATOMIC);
 
 	if (p) {
-		u32 *old_p = __DST_METRICS_PTR(old);
+		struct dst_metrics *old_p = (struct dst_metrics *)__DST_METRICS_PTR(old);
 		unsigned long prev, new;
 
-		memcpy(p, old_p, sizeof(u32) * RTAX_MAX);
+		refcount_set(&p->refcnt, 1);
+		memcpy(p->metrics, old_p->metrics, sizeof(p->metrics));
 
 		new = (unsigned long) p;
 		prev = cmpxchg(&dst->_metrics, old, new);
 
 		if (prev != old) {
 			kfree(p);
-			p = __DST_METRICS_PTR(prev);
+			p = (struct dst_metrics *)__DST_METRICS_PTR(prev);
 			if (prev & DST_METRICS_READ_ONLY)
 				p = NULL;
+		} else if (prev & DST_METRICS_REFCOUNTED) {
+			if (refcount_dec_and_test(&old_p->refcnt))
+				kfree(old_p);
 		}
 	}
-	return p;
+	BUILD_BUG_ON(offsetof(struct dst_metrics, metrics) != 0);
+	return (u32 *)p;
 }
 EXPORT_SYMBOL(dst_cow_metrics_generic);
 
@@ -312,101 +222,134 @@ void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old)
 {
 	unsigned long prev, new;
 
-	new = ((unsigned long) dst_default_metrics) | DST_METRICS_READ_ONLY;
+	new = ((unsigned long) &dst_default_metrics) | DST_METRICS_READ_ONLY;
 	prev = cmpxchg(&dst->_metrics, old, new);
 	if (prev == old)
 		kfree(__DST_METRICS_PTR(old));
 }
 EXPORT_SYMBOL(__dst_destroy_metrics_generic);
 
-/**
- * __skb_dst_set_noref - sets skb dst, without a reference
- * @skb: buffer
- * @dst: dst entry
- * @force: if force is set, use noref version even for DST_NOCACHE entries
- *
- * Sets skb dst, assuming a reference was not taken on dst
- * skb_dst_drop() should not dst_release() this dst
- */
-void __skb_dst_set_noref(struct sk_buff *skb, struct dst_entry *dst, bool force)
+struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie)
 {
-	WARN_ON(!rcu_read_lock_held() && !rcu_read_lock_bh_held());
-	/* If dst not in cache, we must take a reference, because
-	 * dst_release() will destroy dst as soon as its refcount becomes zero
-	 */
-	if (unlikely((dst->flags & DST_NOCACHE) && !force)) {
-		dst_hold(dst);
-		skb_dst_set(skb, dst);
-	} else {
-		skb->_skb_refdst = (unsigned long)dst | SKB_DST_NOREF;
-	}
+	return NULL;
 }
-EXPORT_SYMBOL(__skb_dst_set_noref);
 
-/* Dirty hack. We did it in 2.2 (in __dst_free),
- * we have _very_ good reasons not to repeat
- * this mistake in 2.3, but we have no choice
- * now. _It_ _is_ _explicit_ _deliberate_
- * _race_ _condition_.
- *
- * Commented and originally written by Alexey.
- */
-static void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
-		       int unregister)
+u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old)
 {
-	if (dst->ops->ifdown)
-		dst->ops->ifdown(dst, dev, unregister);
-
-	if (dev != dst->dev)
-		return;
+	return NULL;
+}
 
-	if (!unregister) {
-		dst->input = dst->output = dst_discard;
-	} else {
-		dst->dev = dev_net(dst->dev)->loopback_dev;
-		dev_hold(dst->dev);
-		dev_put(dev);
-	}
+struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
+					     struct sk_buff *skb,
+					     const void *daddr)
+{
+	return NULL;
 }
 
-static int dst_dev_event(struct notifier_block *this, unsigned long event,
-			 void *ptr)
+void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
+			       struct sk_buff *skb, u32 mtu,
+			       bool confirm_neigh)
 {
-	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-	struct dst_entry *dst, *last = NULL;
-
-	switch (event) {
-	case NETDEV_UNREGISTER_FINAL:
-	case NETDEV_DOWN:
-		mutex_lock(&dst_gc_mutex);
-		for (dst = dst_busy_list; dst; dst = dst->next) {
-			last = dst;
-			dst_ifdown(dst, dev, event != NETDEV_DOWN);
-		}
+}
+EXPORT_SYMBOL_GPL(dst_blackhole_update_pmtu);
 
-		spin_lock_bh(&dst_garbage.lock);
-		dst = dst_garbage.list;
-		dst_garbage.list = NULL;
-		spin_unlock_bh(&dst_garbage.lock);
-
-		if (last)
-			last->next = dst;
-		else
-			dst_busy_list = dst;
-		for (; dst; dst = dst->next)
-			dst_ifdown(dst, dev, event != NETDEV_DOWN);
-		mutex_unlock(&dst_gc_mutex);
-		break;
-	}
-	return NOTIFY_DONE;
+void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
+			    struct sk_buff *skb)
+{
 }
+EXPORT_SYMBOL_GPL(dst_blackhole_redirect);
+
+unsigned int dst_blackhole_mtu(const struct dst_entry *dst)
+{
+	unsigned int mtu = dst_metric_raw(dst, RTAX_MTU);
 
-static struct notifier_block dst_dev_notifier = {
-	.notifier_call	= dst_dev_event,
-	.priority = -10, /* must be called after other network notifiers */
+	return mtu ? : dst_dev(dst)->mtu;
+}
+EXPORT_SYMBOL_GPL(dst_blackhole_mtu);
+
+static struct dst_ops dst_blackhole_ops = {
+	.family		= AF_UNSPEC,
+	.neigh_lookup	= dst_blackhole_neigh_lookup,
+	.check		= dst_blackhole_check,
+	.cow_metrics	= dst_blackhole_cow_metrics,
+	.update_pmtu	= dst_blackhole_update_pmtu,
+	.redirect	= dst_blackhole_redirect,
+	.mtu		= dst_blackhole_mtu,
 };
 
-void __init dst_init(void)
+static void __metadata_dst_init(struct metadata_dst *md_dst,
+				enum metadata_type type, u8 optslen)
+{
+	struct dst_entry *dst;
+
+	dst = &md_dst->dst;
+	dst_init(dst, &dst_blackhole_ops, NULL, DST_OBSOLETE_NONE,
+		 DST_METADATA | DST_NOCOUNT);
+	memset(dst + 1, 0, sizeof(*md_dst) + optslen - sizeof(*dst));
+	md_dst->type = type;
+}
+
+struct metadata_dst *metadata_dst_alloc(u8 optslen, enum metadata_type type,
+					gfp_t flags)
+{
+	struct metadata_dst *md_dst;
+
+	md_dst = kmalloc(struct_size(md_dst, u.tun_info.options, optslen),
+			 flags);
+	if (!md_dst)
+		return NULL;
+
+	__metadata_dst_init(md_dst, type, optslen);
+
+	return md_dst;
+}
+EXPORT_SYMBOL_GPL(metadata_dst_alloc);
+
+void metadata_dst_free(struct metadata_dst *md_dst)
 {
-	register_netdevice_notifier(&dst_dev_notifier);
+#ifdef CONFIG_DST_CACHE
+	if (md_dst->type == METADATA_IP_TUNNEL)
+		dst_cache_destroy(&md_dst->u.tun_info.dst_cache);
+#endif
+	if (md_dst->type == METADATA_XFRM)
+		dst_release(md_dst->u.xfrm_info.dst_orig);
+	kfree(md_dst);
+}
+EXPORT_SYMBOL_GPL(metadata_dst_free);
+
+struct metadata_dst __percpu *
+metadata_dst_alloc_percpu(u8 optslen, enum metadata_type type, gfp_t flags)
+{
+	int cpu;
+	struct metadata_dst __percpu *md_dst;
+
+	md_dst = __alloc_percpu_gfp(struct_size(md_dst, u.tun_info.options,
+						optslen),
+				    __alignof__(struct metadata_dst), flags);
+	if (!md_dst)
+		return NULL;
+
+	for_each_possible_cpu(cpu)
+		__metadata_dst_init(per_cpu_ptr(md_dst, cpu), type, optslen);
+
+	return md_dst;
+}
+EXPORT_SYMBOL_GPL(metadata_dst_alloc_percpu);
+
+void metadata_dst_free_percpu(struct metadata_dst __percpu *md_dst)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		struct metadata_dst *one_md_dst = per_cpu_ptr(md_dst, cpu);
+
+#ifdef CONFIG_DST_CACHE
+		if (one_md_dst->type == METADATA_IP_TUNNEL)
+			dst_cache_destroy(&one_md_dst->u.tun_info.dst_cache);
+#endif
+		if (one_md_dst->type == METADATA_XFRM)
+			dst_release(one_md_dst->u.xfrm_info.dst_orig);
+	}
+	free_percpu(md_dst);
 }
+EXPORT_SYMBOL_GPL(metadata_dst_free_percpu);